Centerimeter



is secured to the threaded portion 40 of the intermediate sleeve 34, and locked in place by virtue of set screw 44.

The outer sleeve 3| is provided with two threaded openings 38 so as to receive locating or bore engaging pins 31 when in the position indicated in Figure 3. The range of adjustment of measurements extends to the reading or graduations 45 of the sleeve 2 5 or its surface 29. The surfaces 29 and 3l) carry the graduatlons 45 and the indicator mark 46, respectively,for reading the measurements in thousandths or in ten thou:-v sandth parts of an inch. When placed in the right hand threaded portion 38, the pin A31 will span a greater distance increased by an increment equivalent to the center to ments between left hand and V74the right hand threaded openings 38.

will be in tangential relationship and contact with the side walls of the opening I 09. When th'e tool is thus placed into the opening, the imaginary center of the opening |09 becomes co-axlally aligned with the actual center of the well I6, so that instrument I1 may be positioned therein, and relative measurement therefrom lnscribed or circumscribed on the surface of block I2 with reference to the opening |09.

The Y tips 42 are preferably hardened and ground, so th'at they may be effectively utilized without wear when placed in larger openings 43,

of a piece of work, in which the instrument is to L tractor, generally, designated It is to be noted that the intermediate sleeve 34 is provided with a'threaded portion 35, and an enlarged clearance bore 36. The tip of the knob-l|| is knurled at 41 and graduated and demarcated into twenty-five divisions each indicating one thousandth'. part of an inch, and

aligning with the indicator mark 49. The operation of the knob is similar to micrometer measuring instrument construction, so that the graduations on the scale 45 each indicate twenty-live thousandths of an inch, each being further subdivided into unit thousandths on the dial 48. Rotation ofthe knob or cap 4| one complete turn causes the indicator 46 to move one division on the calibration 45 and thus the readings are, for each graduation 45, twenty-ve thousandths of an inch, whereas for each' graduation on the scale 48 the reading is one one-thousandth of an inch, and the instrument'is read the same as a micrometer would be read.

The tip 42 further enhances theA value of the measuring instrument, inasmuchA as the range is increased to a greater distance and on the instrument or-withinstructions accompanying the said instrument, a certain standard will be indicated for the hole 38,?as well as for. the use of the tip 42, which standard, or measurement, will be added to the actual sum of th'e readings on the calibrations and 48, respectively.

. When the knob 4| is rotated, the threaded screw 32 being `providedwithforty threads-per inch causes the indicator 46 totravel onedivision relative to the calibration 45, provided the knob lis rotated clockwise, or when rotated counter-clockwise the` indicator moves in the opposite direction. When the knob 4| is rotated clockwise, an observer looking fromthe leg end toward the center hub I5, that rotationcauses the headed intermediate sleeve l34 to rotate therewith, which h'olds in confinementthe outer sleeve 3| 4causing it to move together therewith; but the outer sleeve 3| because of the slotted portion 39 therein, will prevent theouter sleeve from rotating, be,- cause the pin 3 1` is located in this slot, and thus will cause the sleeve 3|)` to move outwardly, causing the indicator-,mark 46 to travel to the right,

, and when a counter-clockwise movement is used,

the pin 31 will travel inwardly, and also the mark In order to utilize the instrument, the bore or opening diameter lis rst determined, then each leg is set to a radial measurement, or vone half of 'the diameter measurement of the opening. |09, which' will cause the pins 31 to be equidistant from the center of the opening |09, and also from the center of the well I6, thus an outer lineal ,element ofthe cylindrical surface `ofthe1 pin 31 van internal threaded portion s be used.

The views in Figures 5 and 6 show a 360 pro- I8, which has a top surface I9, and a formed conical well portion 20', having its opening 2| relatively congruent with the well I6, so as to frictionally engage therein, permitting the center 23 to be used for positioningthe legs of instrument I1 therein, and the calibrations 22 running from zero to 360 may facilitate angular measurements and layout of measurements required on the surface of work pieceI2.

In Figure 7, I use an outer sleeve 50 which has a threaded shank 5I to be threaded and secured to the hub I5 and held in locked engagement by virtue of set screw 53. The outer sleeve 50 has 52, substantially, thruout its effective working length, in which is fitted a headed bolt 58 having a threaded portion ,to fit within the thread of the outer sleeve 50, and provided with a reduced body portion 64, terminating in a threaded portion 65 to engage the cap or knob 6I, and be firmly locked in place by the set screw 66. The knob BI is suitably knurled at 62 and graduated at 63 from zero to twentylive thus registering thousandths of an inch'. The intermediate sleeve 59 is a working t in between the connes of the edge 68 of the knob 6I, and the inner edge 61 of the threaded head 58, the said sleevel 59 being also provided with threaded portions 56 and 51.

The pins 55 are secured interchangeably either to the threaded portion 56 or 51 thus increasing the span or range of adjustment, the said Vpins 55 operating slldably within the confines of the slot 54 in the outer sleeve 50 thus preventing the sleeve 59 from rotating. When it rotates the threaded the knob `62 is rotated, head 58 within the threaded portion of the outer sleeve 50, thus moving the same in or out, and moving the sleeve 5 9 in or out, the sleeve 59 being prevented from rotation because the pin 55 operates slidably in the slotted portion 54 of the outer sleeve 5I1which is xedly secured to the hub I5. This form is usedy in the same manner as elucidated, for the form in Figures 1 to 4 heretofore described.

Figures 8 and 9 are similar in construction, but slightly modied, wherein the pins 1| are threaded into openings 12 or openings 13 in order to increasethe range of adjustment, and the conical tip of the knob 96 of the rotating knob is also used in the self-same manner as illustrated in Figure 3. In this form, I provide an outer sleeve 69 which' is secured to the hub I5 by virtue of its projection or extension 10 seating against a recess portion in the hub I5, and in which the pin 1I. is alsosecured. The said sleeve is provided with a recess 19, and a counter-bore recess 14 in which is fitted the scale plate 15 which has the calibrations 86, each graduation being ltwenty- .ve thousandths of4 an inch apart from its adjacent graduation, the said scale 15 being adjustably positionable with respect to its elongated slot 11 and the screws 16, which have their threaded bodies 18 secured to threaded openings in the sleeve 69.

The indicator 80 is provided with a line of demarcation 85 which registers with the graduations 86 when it is aligned therewith, and the element 80 is likewise adjustably confined in the slot 81 by its slotted means 84, which permits lateral adjustment of the indicator bushing 80, held in place by the screw 8| and the intermediate shoulder 82, its threaded tip 83 being secured to th'e intermediate sleeve 89. The said sleeve 89 is provided with an internal thread of 40 pitch design-ated 90, in which the intermediate sleeve B9 is secured to a threaded plug 88, which in turn is held securely in place by the counter-sunk screw 94, having its body 93 threaded into th'e hub l5.

Within the threaded portion 99, operates a threaded head 92, which has a reduced body 9|, and a further reduced shoulder extension 98, terminating in a threaded portion to which the knob 9B is secured, and held firmly in place by the set screw |0I. The knob 96 is also counter-bored at 91 in order to accommodate a resilient element, or spring 99, housed about the said shoulder 98, the sleeve 89 being confined between the bottom |02, or closed end |02 of the outer sleeve 69, thus the spring 99 offers suitable tensioning contact preventing dirt from entering into the working mechanism of the device. When the knob 96 is grasped by the knurled portion 95 and rotated, it will take therewith the inner element 9| which works its threaded head 92 in or out of the thread 90 of the intermediate sleeve 89, and thus causes the -outer sleeve 69 to move along with it, because the indicator bushing 8| confines the intermediate sleeve 89 and prevents rotation thereof, thus the sleeve B9 moves outwardly with the pin 1| and the knob 96, and the device may b-e used in the self-same manner as the devices represented by the aforementioned and described forms of my invention.

I-t is to be noted, that the scale and the indicator 80 both provide for relative adjustment for wear if that should be necessary, and the scale 15 may be easily replaced, or if the graduations are worn, or for any other reason removal should become necessary.

In the form indicated in Figure 11, the construction is exactly the same as in Figures 8 and 9 with the exception that the sleeve 59 is provided with a partially open end |02, having a threaded portion |01 therein to receive the threaded end |09 of the bushing |95, which is rotatably confined on the shank or extension 98, with the exception that the shank 98 in this instance has a smooth end |03 which is held in place, in assembly, with the knob by means of set screw |94. A spring 99 is also used in order to confine the said bushing frictionally and provide a dust-proof arrangement for the satisfactory operation of the unit. A shoulder, or a collar |08 may be used for seating the bushing |05.

Having thus disclosed and described my invention, what I claim as novel and desire to secure by Letters Patent, is:

A centerimeter comprising, a hub having a rust-o-ccnical well at its mid-point, and at least three independently extensible .and retractable leg locating means adapted to locate the said well concentrically with respect to an opening, the said locating means including, an outer sleeve secured to the said hub. and provided with diametrioally opposed slotted portions, one of said slotted portions provided with a calibrated scale of measurement, a threaded stud secured concentrically to the said outer sleeve, an inner sleeve rotatably engaging the said threaded stud, an intermediate sleeve mounted between the said outer and inner sleeves and provided with an indicator marking cooperating with the said calibrated scale, a locating lpin element secured to the said intermediate sleeve and slidably operative in the other of said slotted portions in the said outer sleeve, and a cap .element secured to one end of said inner sleeve and provided with a calibrated scale of measurement positioned at right angles to the said rst mentioned scale and cooperating with an indicator demarcation on the adjacent end of said intermediate sleeve, the said conical well having its apex in the geometric plane of the top surface of the said opening.

RICHARD H. COLWILL.

REFERENCES CITED r.The following references are of record in the iile of this patent:

UNITED STATES PATENTS Number Name Date 193,398 Crandall July 24, 18'17 1,846,781 Buchmuller Feb. 23, 1932 FOREIGN PATENTS Number Country Date 60,558 Germany Jan. 13, 1892 195,701 Great Britain Apr. 12, 1923 

